DUTY[2:0]
Duty (NB_COM)
Recommended Bias
COM Pins
0x4
6
1/3
COM0..5
0x5
8
1/4
COM0..7
The CTRLA.BIAS[1:0] bit field defines the number of bias voltage:
Table 43-2. Bias Selection (CTRLA.BIAS)
BIAS[1:0]
Description
00
Static
01
1/2
10
1/3
11
1/4
The LCD controller will drive different waveforms according to the different bias configurations. The LCD
controller supports two types of driving waveform, bit-inversion (type A, standard) or frame-inversion (type
B, low-power). The frame-inversion mode has a lower switching frequency than the bit-inversion mode,
and thus reduced power consumption comparing to standard waveform. Both waveform modes have the
same period, and their DC-component is null.
By default the low-power waveforms mode is enabled. To select frame-inversion mode, write a zero in the
Waveform Mode bit in Control A register (CTRLA.WMOD). To select bit-inversion mode, write a '1' to
CTRLA.WMOD.
The following section illustrates how the SLCD controller drives different LCD panels.
For static bias, standard and low-power waveform are identical. However, for 1/2, 1/3 and 1/4 bias, low-
power waveform provides a lower toggle rate comparing to the standard waveform.
Figure 43-4. Static Bias Waveform template
Voltage Level Definition
V1 : VLCD
V0 : 0
COM Pixel
Select
Waveform V0
V1
SEG Pixel
On
Waveform
V0
V1
SEG Pixel
Off
Waveform
V0
V1
Pixel
V0
-V1
V1
Pixel
On
V0
-V1
V1
Pixel
Off
COM Waveform
Template
SEG Waveform
Template
Atmel SAM L22G / L22J / L22N [DATASHEET]
Atmel-42402E-SAM L22G / L22J / L22N_Datasheet_Complete-07/2016
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